﻿#region Copyright information
// 
// Copyright © 2005-2013 Yongkee Cho. All rights reserved.
// 
// This code is a part of the Biological Object Library and governed under the terms of the
// GNU Lesser General  Public License (LGPL) version 2.1 which accompanies this distribution.
// For more information on the LGPL, please visit http://bol.codeplex.com/license.
// 
// - Filename: ConditionalProbabilityTable.cs
// - Author: Yongkee Cho
// - Email: yongkeecho@gmail.com
// - Date Created: 2012-09-06 11:39 AM
// - Last Modified: 2013-01-25 3:59 PM
// 
#endregion
using System;
using System.Collections.Generic;
using System.Linq;

namespace BOL.Linq.Probability
{
    public static partial class Probability
    {
        public static IDictionary<Tuple<TKey1, TKey2>, double> ConditionalProbabilityTable<TSource, TKey1, TKey2>(this IEnumerable<TSource> source, Func<TSource, Tuple<TKey1, TKey2>> keySelector)
        {
            var list = source.ToList();
            var n = list.Count;

            return list.GroupBy(keySelector).ToDictionary(x => x.Key, x => x.Count() / (double)n);
        }
    }
}
